Thermodynamic considerations on the hydration mechanisms of Ca3SiO5 and Ca3Al2O6

Stein, H.N.

doi:10.1016/0008-8846(72)90039-7

Cited by 35 publications

(13 citation statements)

References 9 publications

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“…The curve with higher Si concentrations, curve B, was obtained solely from experiments conducted during the first several hours of C 3 S hydration. Thermodynamic considerations [48] excluded the possibility that curve B represented a metastable solubility curve for C 3 S. It was thus presumed that curve B represented a metastable solubility curve for the initial product formed as a layer on the C 3 S surface. † If viewed from the perspective of the liquid phase, this statement is equivalent to ensuring that the same solubility is obtained commencing from undersaturation and supersaturation with respect to C-S-H of a given Ca/Si ratio.…”

Section: Previous Solubility Relationsmentioning

confidence: 99%

Solubility and structure of calcium silicate hydrate

Chen

Thomas

Taylor³

et al. 2004

Cement and Concrete Research

739

414

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C-S-H, the poorly crystalline calcium silicate hydrate formed in cement paste and aqueous suspension, is characterized by extensive disorder and structural variations at the nanometer scale. An analysis of new and published solubility data for C-S-H formed by different preparation methods and with a broad range of compositions illustrates a previously unrecognized family of solubility curves in the CaO-SiO 2 -H 2 O system at room temperature. As demonstrated by 29 Si magic-angle spinning (MAS) NMR data and by charge balance calculations, the observed differences in solubility arise from systematic variations in Ca/Si ratio, silicate structure, and Ca-OH content. Based on this evidence, the family of solubility curves are interpreted to represent a spectrum of metastable C-S-H phases whose structures range from purely tobermorite-like to largely jennite-like. These findings give an improved understanding of the structure of these phases and reconcile some of the discrepancies in the literature regarding the structure of C-S-H at high Ca/Si ratios.

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Section: Previous Solubility Relationsmentioning

confidence: 99%

Solubility and structure of calcium silicate hydrate

Chen

Thomas

Taylor³

et al. 2004

Cement and Concrete Research

739

414

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“…Investigating the dissolution mechanism for C 3 S is not the focus of this work. Thus, while there are a number of hypothesis presently being debated, including the etch‐pit transition and protective layer conjectures, the site deactivation hypothesis was adopted to be consistent with Bullard and Flatt's recent work; an interpretation wherein C 3 S approaches a near “pseudo‐equilibrium” at a much lower effective equilibrium constant of 10 −17 , whereas the calculated value is nominally 3 . This observation could be the result of the formation of a hydroxylated surface or site poisoning by adsorption or a mechanistic transition from etch pit to step retreat dissolution.…”

Section: Multi‐ionic Continuum‐based Modelmentioning

confidence: 83%

A Multi‐Ionic Continuum‐Based Model for C₃S Hydration

Gottapu

Biernacki

2015

J. Am. Ceram. Soc.

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A computationally efficient strategy for modeling tricalcium silicate hydration based on through‐solution‐phase kinetics is demonstrated. This study extends a recently introduced advanced continuum‐based single particle model by including rigorous multi‐ionic transport, nonlinear reversible reaction kinetics and portlandite precipitation. Model parameters were either fixed based on known values, estimated using experimental measures or extracted by model fitting to benchmark experimental datasets. The model is now able to generate calorimetric hydration and evolution of pore solution chemistry responses that are in good agreement with available experimental results and predictions of other multiphysical modeling platforms. Once calibrated, the model was tested to see if it could predict the effect of water to cement ratio (w/c) and particle size on hydration outcomes. The findings support the need for a mechanism that limits the volume into which product can form.

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“…Thermodynamic calculations similar to those in Stein 17 indicate that the solubility product of C 3 S should be K sp ≈3 when defined by the net dissociation reaction …”

Section: Introductionmentioning

confidence: 79%

“…However, the observed ion activity product, K , is much less than 3, by about 17 orders of magnitude, immediately after Stage 1 (A. Nonat, personal communication) 17,18 . Therefore, reduction in the rate of C 3 S dissolution would appear to be caused by something other than near equilibrium between C 3 S and the solution.…”

Section: Introductionmentioning

confidence: 99%